Structure–Property Relationships in Mg-MOFs: Dimensional Effects on the Electrocatalytic Detection of Dopamine

Abstract

Abstract The well-defined crystalline structures of metal–organic frameworks (MOFs) offer a versatile platform for investigating structure–property relationships in electrocatalysis. Herein, we report the synthesis of two magnesium-based MOFs (Mg-MOFs, MOF-1 and MOF-2) constructed from Mg2+ ions and a tetraphenylethylene (TPE)-based fluorinated ligand (H4tmpe-F). Through precise modulation of solvothermal conditions, distinct structural dimensionalities were achieved, allowing for a comparative study of their electrochemical behaviors. When employed as electrocatalysts for dopamine (DA) oxidation, the MOFs exhibited dimension-dependent activity. Notably, MOF-2, featuring a 2D framework, demonstrated significantly enhanced electrocatalytic performance compared to MOF-1, which features a 1D chain-like structure, yielding a low detection limit of 12.9 nM and a high sensitivity of 1759.7 μA·mM–1·cm–2. To elucidate the origin of this reactivity difference, density functional theory (DFT) calculations were performed. The theoretical results reveal that the specific structural arrangement of MOF-2 facilitates stronger adsorption affinity toward DA molecules and optimizes the reaction pathway energetics. This work highlights the critical role of structural dimensionality in tuning the electrochemical properties of Mg-MOFs and provides a fundamental understanding of their catalytic mechanisms at the molecular level.